The existing bench drilling and tapping machine tool usually includes a base, a column, a transverse arm and drilling and tapping device. The lower end of the column is connected to the base, and the transverse arm is horizontally connected to the column. One end of the transverse arm is connected to the column, the other end to the drilling and tapping device. The machine tool is driven through belt by the motor. It's not easy or even impossible for the above drilling and tapping device to process a workpiece fixed on the base or the different positions of the same workpiece. It needs operator holding the workpiece to process, which is unsafe and low accuracy. Moreover, as with the only belt driving, it's of easy slippery and without high pulling torque.